System and method for critical dimension reduction and pitch reduction

ABSTRACT

A method of forming a feature includes forming a mask of a first material on an underlying layer, the mask having an incorrect profile. The profile of the mask is corrected and a feature is formed in the underlying layer. A system for forming a feature is also disclosed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to forming devices in asubstrate, and more particularly, to methods and systems for reducingthe critical dimension and reducing the pitch in lithographic systemsand processes.

2. Description of the Related Art

Reducing the device size (i.e., critical dimension of the devices) andincreasing the density of the devices (i.e., pitch reduction) is aconstant goal in semiconductor production. These goals aid in reducingthe power consumption and cost of the semiconductor device being formedwhile also increasing the performance of the semiconductor device.Unfortunately, the reduced critical dimension and/or the reduced pitchoften require new and expensive equipment to achieve these goals. By wayof example, if a photolithographic system is optimized for formingdevices having a critical dimension of about 0.4 micron, and a desiredcritical dimension is about 0.3 micron (an about 25% smaller criticaldimension) then the photolithographic system must be replaced and/orextensively modified to accurately achieve the 0.3 micron criticaldimension.

Further, more devices having a 0.3 micron critical dimension can beformed in the same area of the substrate (i.e., the pitch can bereduced). By way of example, about 30 devices can be formed in a widthof about 24 micron having if each of the devices has a 0.4 microncritical dimension and about 0.4 micron pitch between each device. Incomparison, about 40 devices can be formed in the same 24 micron widthif each device has a 0.3 micron critical dimension and about 0.3 micronpitch between each device. The photolithographic system optimized forforming devices having the critical dimension of about 0.4 micron pitchmust be replaced and/or extensively modified to accurately achieve the0.3 micron pitch.

As a result, the constant drive for reduced critical dimension anddecreased device pitch add to the capital cost of producingsemiconductors. In view of the foregoing, there is a need for a systemand method for extending the capabilities of a photolithographic processso as to allow reducing the critical dimension and reducing the pitch ofthe devices.

SUMMARY

Broadly speaking, the present invention fills these needs by providing asystem and method for extending the capabilities of a photolithographicprocess so as to allow reducing the critical dimension and reducing thepitch of the devices. It should be appreciated that the presentinvention can be implemented in numerous ways, including as a process,an apparatus, a system, computer readable media, or a device. Severalinventive embodiments of the present invention are described below.

One embodiment provides a method of forming a feature. The methodincludes forming a mask of a first material on an underlying layer, themask having an incorrect profile. Correcting the profile of the mask andforming a feature in the underlying layer. The can also include removingthe mask.

Forming the mask on the underlying layer can include forming the maskwith a photolithographic process. The photolithographic process isoptimized for a first critical dimension and the mask has a secondcritical dimension that is substantially less than the first criticaldimension.

Forming the mask on the underlying layer can include forming the maskwith a photolithographic process, the photolithographic process isoptimized for a first density and the mask has a second density that issubstantially greater than the first density.

Correcting the profile of the mask can include removing a first portionof the sides of the mask. Removing a first portion of the sides of themask can include at least one of a low pressure etch process or aselective deposition process. The low pressure etch process can includean etch process pressure of less than about 70 milliTorr. The selectivedeposition process can include a deposition process pressure of greaterthan about 50 milliTorr.

Correcting the profile of the mask can include adding a second portionmaterial to the sides of the mask. Adding a second portion of materialto the sides of the mask can include at least one of a low pressure etchprocess or a selective deposition process.

The method can also include narrowing the corrected profile of the mask.Narrowing the corrected profile of the mask can include adding a thirdportion of material to the sides of the mask. The feature formed in theunderlying layer can be substantially equal to or less than the narrowedmask.

Another embodiment provides a method of forming a feature. The methodincludes forming a mask of a first material on an underlying layer. Themask having an incorrect profile and the mask is formed with aphotolithographic process. The photolithographic process is optimizedfor a first critical dimension and the mask has a second criticaldimension that is substantially less than the first critical dimension.The profile of the mask is corrected including removing a first portionof the sides of the mask and adding a second portion of material to thesides of the mask. A feature can be formed in the underlying layer. Thefirst portion can be removed from the sides of the mask substantiallysimultaneously with the second portion of the material being added tothe sides of the mask.

Yet another embodiment provides a system for forming devices in asubstrate. The system includes a process chamber for enclosing asubstrate for processing. The process chamber coupled to a gas manifoldand a controller. Multiple process gas sources are fluidly coupled tothe gas manifold. The gas manifold coupled to the controller and thecontroller includes a recipe. The recipe including logic for correctinga profile of a mask formed on the substrate, the mask being formed of afirst material.

The logic for correcting the profile of the mask includes logic forremoving a first portion of the sides of the mask and logic for adding asecond portion of material to the sides of the mask. The recipe can alsoinclude logic for narrowing the corrected profile of the mask.

Other aspects and advantages of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, illustrating by way of example the principles ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be readily understood by the followingdetailed description in conjunction with the accompanying drawings.

FIG. 1A is a cross-sectional view of a mask formed on a semiconductorsubstrate, in accordance with one embodiment of the present invention.

FIG. 1B is a cross-sectional view of features formed using the mask, inaccordance with one embodiment of the present invention.

FIG. 1C is a cross-sectional view of features, in accordance with oneembodiment of the present invention.

FIG. 1D is a cross-sectional view of 0.3 micron mask formed by the 0.4micron-optimized photolithographic process, in accordance with oneembodiment of the present invention.

FIG. 1E is a cross-sectional view of the features formed by the 0.3micron mask, in accordance with one embodiment of the present invention.

FIG. 1F is a detailed view of the profile of a mask, in accordance withone embodiment of the present invention.

FIG. 2 is a flowchart of the method operations for correcting theprofile of the mask, in accordance with one embodiment of the presentinvention.

FIGS. 3A and 3B are a cross-sectional view of features formed in theunderlying intermediate layer, in accordance with one embodiment of thepresent invention.

FIG. 4 is a cross-sectional view of features formed in the underlyingintermediate layer, in accordance with one embodiment of the presentinvention.

FIG. 5 is flowchart of the method-operations for narrowing a mask, inaccordance with one embodiment of the present invention.

FIG. 6 is flowchart of the method-operations for gas modulation forcorrecting a profile of a mask, in accordance with one embodiment of thepresent invention.

FIG. 7 is a block diagram of a system, in accordance with one embodimentof the present invention.

DETAILED DESCRIPTION

Several exemplary embodiments for a system and method for extending thecapabilities of a photolithographic process so as to allow reducing thecritical dimension and reducing the pitch of the devices will now bedescribed. It will be apparent to those skilled in the art that thepresent invention may be practiced without some or all of the specificdetails set forth herein.

The various embodiments described herein provide a system and method forenhancing the performance of existing photolithographic processes andsystems. As a result, a photolithographic process and system can be usedto form semiconductor devices having smaller critical dimension andincreased device density.

FIG. 1A is a cross-sectional view 100 of a mask 104A formed on asemiconductor substrate 102, in accordance with one embodiment of thepresent invention. The mask 104A is formed using a photolithographicprocess optimized for forming devices having a critical dimension (i.e.,width) of about 0.4 micron or larger features (i.e., a 0.4 micronprocess). The 0.4 micron process forms openings 104B in the maskmaterial 104. Typically, the 0.4 micron process includes aphotolithographic sub process applied to a photoresist mask material 104(or other photosensitive material). The exposed portions 104A of themask material 104 are transformed by exposure to the light. Thenon-exposed portions (not shown) are removed in a subsequent cleaningprocess to form the openings 104B between the mask 104A.

Each of the removed portions 104B has a width of about 0.4 micron. Eachof the removed portions 104B are separated by the mask 104A, that isequal to or larger than about 0.4 micron in width.

The photolithographic process used to form the mask 104A is optimized toform a mask having widths of about 0.4 micron or more in width and adensity of about 0.4 micron or more apart. As a result, mask 104A has anoptimum profile. The optimum profile mask 104A has sides that aresubstantially vertical. By way of example, the sides of the mask 104Aform an angle θ between about 75 and about 90 degrees to the top surfaceof the mask layer 104. Further, substantially all of the material in themask layer 104 has been removed in the openings 104B such that theoptimum profile mask 104A have a bottom surface 104C that issubstantially parallel to the top surface of the mask layer 104.

FIG. 1B is a cross-sectional view 100′ of features 102A formed using themask 104A, in accordance with one embodiment of the present invention.The substrate 101 has an intermediate layer 102 formed thereon. The mask104A is formed on the top surface of the intermediate layer 102 asdescribed above in FIG. 1A. An etching process can be used to formfeatures 102A in the intermediate layer 102.

The shape of the mask 104A helps ensure the shape of the resultingfeatures 102A. By way of example, if the mask 104A has an optimumprofile then the resultant features 102A will in many cases, also havean optimum profile of substantially the same width. Similarly, if themask 104A does not have an optimum profile then the resultant features102A will more than likely have a less than optimum profile (e.g., lessthan optimum and/or inconsistent depth and/or width).

FIG. 1C is a cross-sectional view 100″ of features 102A, in accordancewith one embodiment of the present invention. After the mask 104A isused to form the features 102A as described above in FIG. 1B, the maskis no longer needed. As shown in FIG. 1C, the mask 104A has beenremoved. Typically the mask is removed by a chemical mechanicalplanarization or a selective etching process or any other suitableprocess to remove the mask 104A. The substrate is then ready forsubsequent processing. By way of example the features 102A can be filledwith a conductive material (e.g., copper, copper alloy or otherconductive materials) to form a conductive trace or a via or otherdevice.

As the photolithographic process is optimized to form features 102Ahaving widths of about 0.4 micron or more in width and about 0.4 micronor more apart, then the photolithographic process cannot accurately formfeatures having width or densities less than about 0.4 micron. FIG. 1Dis a cross-sectional view of 0.3 micron mask 108A formed by the 0.4micron-optimized photolithographic process, in accordance with oneembodiment of the present invention. FIG. 1F is a detailed view of theprofile of a mask 108A, in accordance with one embodiment of the presentinvention. As the 0.4 micron-optimized photolithographic process is notoptimized to produce the mask 108A having widths of about 0.3 micron,the mask 108A does not have an optimum profile. By way of example, thebottom 108C of the openings 108B is rounded or may even be pointed andis not substantially parallel to the top surface of the upper layer 104.Further, the mask 108A has sides that form an angle θ′ less than about75 degrees to the top surface of the mask layer 104.

FIG. 1E is a cross-sectional view 120′ of the features 118A-F formed bythe 0.3 micron mask 108A, in accordance with one embodiment of thepresent invention. As shown, the features 118A-F formed in theintermediate layer 102 have very inconsistent and unsymmetrical profile,depth and width. Further, the features 118A-F undercut the mask 108A.Further still, the opening to the features 118A-F is too narrow and hasinconsistent widths. Once the mask 108A is removed, the inconsistentwidth of the openings to the features 118A-F will cause inconsistentfilling of the features and thus provide poor contact to the underlyinglayer 101 and/or poor contact to a conductive layer that may besubsequently formed on top of the filled features 118A-F.

In summary the mask 108A has undesirable, excess material 124 remainingat the bottom 108C of the opening 108B. Further, too much material 122has been removed from the top portion of the mask 108A causing arounding-off of the top edges of the feature. If the mask 108A were usedto attempt to form features (e.g., features 102A) in the intermediatelayer 102, the resulting features would not have a predictable andoptimum profile as the profile of the mask 108A is not optimum.

One embodiment of the present invention provides a system and method forcorrecting the profile of the mask 108A to an optimum profile shape.Correcting the profile of the mask 108A can include replacing thematerial 122 that was removed from the top edge of the mask 108A.Correcting the profile of the mask 108A can also include removing theundesirable excess material 124 remaining at the bottom 108C of theopening 108B.

FIG. 2 is a flowchart of the method operations 200 for correcting theprofile of the mask 108A, in accordance with one embodiment of thepresent invention. In an operation 205, a mask is formed on anunderlying layer. The mask can have an incorrect profile (e.g., mask108A).

In an operation 210, the profile of the mask 108A is corrected. Theprofile can be corrected by adding material to the top portion 122 ofthe mask 108A. Correcting the profile of the mask 108A can also includeremoving additional material 124 from the bottom portion of the mask108A. The profile of the mask 108A is corrected until the profile has adesirable profile. By way of example, if the bottom of the mask 108C issufficiently cleared of material (e.g., similar to bottom 108C of FIG.1E), however, too much material 122 has been removed from the topportion of the mask 108A, then the only the portions of material 122 maybe added to the mask 108A to correct the profile. The profile of themask 108A can be corrected through gas modulation as will be describedin more detail below.

The profile of the mask 108A can be corrected by applying or depositinga material with a non-uniform (e.g., depth dependent) stickingcoefficient to the sides of the mask. By way of example, a depositing amaterial with a non-uniform sticking coefficient material may build upon the top portions 122 of the sides of the mask faster than at thebottom 108C of the sides of the mask and as a result, the non-uniformsticking coefficient material can replace the material 122 at the topportions of the sides of the mask 108A.

Varying plasma conditions can change the amount of material deposited atdifferent locations within the opening 108B of the mask 108A. Forexample, by increasing the hydrogen to fluorocarbon ratio it is possibleto change from a net etching to net depositing plasma. Additionalprocess parameters such as Argon flow and pressure can be employed tocontrol the relative amounts of deposition and etching which occur atprofile sidewalls (e.g., material 122) and bottom 108C (e.g., material124). More generally, to get a directional etch with little or nosidewall deposition, it is beneficial to employ a low pressure (e.g.,less than about 70 milliTorr), hydrogen free plasma while a netdepositing condition is achievable with a plasma process which utilizeshigher pressure and hydrogen flow. One representative example of arecipe which has net etching characteristics is a plasma chamberpressure of about 30 milliTorr, with plasma power of about 800 watts at27 MHz and 0 watts at 2 MHz, about 180 sccm Argon and about 150 sccmCF₄. In comparison, an example of a net depositing recipe is a plasmachamber pressure of about 70 milliTorr, with plasma power of about 800watts at 27 MHz and 400 watts at 2 MHz, about 240 sccm Argon and about75 sccm CF₄, and about 100 sccm H₂. In the context of integratingreducing critical dimension and pitch, the low pressure etch can removemore material (e.g., material 124) from the bottom 108C of the opening108B in the mask 108A than from the sidewalls of the opening 108B of themask 108A. Removing the material 124 from the bottom 108C of the opening108B in the mask 108A corrects at least a portion of the profile of theopening 108B′ in the mask. A selective deposition process could be usedinstead of or in combination with an etch process at a somewhat lowerpressure. By way of example, the selective deposition process could beapplied at about 70 milliTorr and the etch process be applied at apressure less than 70 milliTorr (e.g., about 50 milliTorr or betweenabout 20 milliTorr and about 70 milliTorr but less than the pressure ofthe selective deposition process). The selective deposition process candeposit more or equivalent material on the sidewalls of the opening 108Bof the mask 108A (e.g., material 122) than on the bottom 108C of theopening 108B in the mask. (For equivalent, what is meant is that if oneetches and removes more material from the bottom than the sidewall andthen deposits equivalent amounts of material on the sidewall and bottom,then the net effect is still an etched feature with a reduced opening108B size.) Adding the additional material 122 to the sidewalls of theopening 108B of the mask 108A not only can iteratively reduce the mask(and as a consequence to be etched feature) dimension, but also cancorrect the profile of the opening 108B′ in the mask 108A. Whether thelow pressure etch process and/or the selective deposition process isused is determined by the specific needs of the mask 108A. By way ofanother example, if the top portion of the profile of the opening 108Bof the mask 108A is acceptable, e.g., material 122 is alreadysubstantially present), then the selective deposition may be attenuated.

In an operation 215, a feature 302A is formed in the underlying layer(e.g., layer 102) using the mask 108A′having the corrected profile. Thecorrected profile of the mask 108A′ allows the features 302 to be formedwith a desirable profile.

FIGS. 3A and 3B are a cross-sectional view 300 of features 302A formedin the underlying intermediate layer 102, in accordance with oneembodiment of the present invention. The 0.3 micron mask 108A was formedusing a photolithographic process optimized for 0.4 micron devicewidths. The 0.3 micron mask 108A had an incorrect profile such as shownin FIGS. 1D-E above. The profile of the opening 108B of the mask 108Awas corrected as described above to form mask 108A′. The correctedprofile of the opening 108B of the mask 108A′ is used to form features302A in the underlying intermediate layer 102.

As described above in FIGS. 1D-3B, an exemplary 0.4 micron mask has beenreduced to form a 0.3 micron mask. It should be understood that similarreduction processes can be employed to reduce other sizes of masks. Byway of example a 0.25 micron mask can be reduced to an about 0.15 micronmask. Similarly, a 0.5 micron mask could be reduced to an about 0.4micron mask.

As described above in FIGS. 1D-3B, a mask can be formed with anincorrect profile such as a mask formed with widths too small for thephotolithographic process employed. Then the profile of the opening 108Bof the mask 108A can be corrected so that it can be used to formfeatures. (e.g., features 302A) that have similar smaller widths thanintended by the photolithographic process employed. The resultingfeatures can also be closer together than intended by thephotolithographic process employed.

FIG. 4 is a cross-sectional view 400 of a feature 402A formed in theunderlying intermediate layer 102, in accordance with one embodiment ofthe present invention. FIG. 5 is flowchart of the method-operations 500for narrowing a mask, in accordance with one embodiment of the presentinvention. In an operation 505, the mask 108A is formed. In an operation510, the profile of the opening 108B of the mask 108A is corrected asdescribed above.

In an operation 515, additional material 422 is added to the sides ofthe opening 108B of the mask 108A to further narrow the opening 108B ofthe mask 108. By way of example, as described above, a 0.4 micronphotolithographic process was used to form a 0.3 micron mask. Theprofile of the 0.3 micron mask was corrected and then used to formfeatures (e.g., features 302A of FIG. 3B above). The features 302A havesubstantially the same width as the opening 108B′ of the mask 108A′(e.g., about 0.3 micron). As shown in FIG. 4, the additional material422 can be added to the sidewalls of the opening 108B″ of the mask 108Ato narrow the opening 108B″ in the mask 108A to substantially less than0.3 micron (e.g., about 0.20 or 0.25 micron width).

The opening 108B″ in the mask 108A can be narrowed by gas modulation.The opening 108B″ in the mask 108A can be narrowed by adding non-depthdependent, uniform sticking coefficient material to the sides of theopening 108B″ of the mask 108A.

As described above, varying plasma conditions can change the amount ofmaterial deposited at different locations within the feature. Forexample, a lower pressure (e.g., less than about 70 milliTorr) etchprocess, such as described above can be at least somewhat directional innature. The low pressure etch can remove more material from the bottom108C of the opening 108B in the mask 108A than from the sidewalls of theopening 108B of the mask 108A. A selective deposition process could beused instead of or in combination with the lower pressure etch process.The selective deposition can be deposit more material on the sidewallsof the opening 108B of the mask 108A than on the bottom 108C of theopening 108B in the mask 108A. Adding the additional material 422 to thesidewalls of the opening 108B of the mask 108A reduces the width of theopening 108B″ in the mask 108A.

In an operation 520, the narrowed opening 108B″ can be used to form asimilarly narrowed feature 402A. By way of example, if the narrowedopening 108B″ has a width of about 0.25 micron then the feature 402A canhave a width of about 0.2 micron to about 0.25 micron.

FIG. 6 is flowchart of the method-operations 600 for gas modulation forcorrecting a profile of a mask, in accordance with one embodiment of thepresent invention. In an operation 605, a substrate 101 is placed in aprocess chamber. The substrate has an undesirable profile as describedin FIGS. 1D-F above. The process chamber can be any suitable processchamber (e.g., a plasma chamber, etch chamber, deposition chamber,etc.).

In an operation 610, a first process is applied to the substrate 101. Byway of example and with reference to FIG. 1F above, the first processcan remove the excess material 124 from the bottom 108C of the opening108B in the mask 108A. The excess material 124 can be removed in aselective etch process.

In an operation 615, a second process can be applied to the substrate101. By way of example and with reference to FIG. 1F above, the secondprocess can add the additional material 122 to the top portion of theopening 108B of the mask 108A. The additional material 122 can bedeposited in a deposition process. It should be understood that theoperations 610 and 615 can occur in any order and even be iterativelyapplied to achieve a desired profile.

If, in an operation 620, the profile of the mask 108A is corrected, thenthe method operations can end. Alternatively, if in operation 620, theprofile of the mask 108A is not yet corrected, then the methodoperations can continue in operation 610. The operations 610 and 615 canalso occur substantially simultaneously.

FIG. 7 is a block diagram of a system 700, in accordance with oneembodiment of the present invention. The system includes a processchamber 702 coupled to a controller 710. The controller 710 includes oneor more recipes 712 for controlling the processes carried out in theprocess chamber 702. One or more process gas sources 720A-N are coupledto the process chamber 702 through a gas manifold 722. The gas manifold722 is coupled to the controller 710. The gas manifold 722 allows thecontroller 710 to control the pressure, flowrate, mixture andconcentration of the process gases from the process gas sources 720A-Nin the processing chamber 702.

With the above embodiments in mind, it should be understood that theinvention may employ various computer-implemented operations involvingdata stored in computer systems. These operations are those requiringphysical manipulation of physical quantities. Usually, though notnecessarily, these quantities take the form of electrical or magneticsignals capable of being stored, transferred, combined, compared, andotherwise manipulated. Further, the manipulations performed are oftenreferred to in terms, such as producing, identifying, determining, orcomparing.

Any of the operations described herein that form part of the inventionare useful machine operations. The invention also relates to a device oran apparatus for performing these operations. The apparatus may bespecially constructed for the required purposes, or it may be ageneral-purpose computer selectively activated or configured by acomputer program stored in the computer. In particular, variousgeneral-purpose machines may be used with computer programs written inaccordance with the teachings herein, or it may be more convenient toconstruct a more specialized apparatus to perform the requiredoperations.

The invention can also be embodied as computer readable code on acomputer readable medium. The computer readable medium is any datastorage device that can store data which can thereafter be read by acomputer system. Examples of the computer readable medium include harddrives, network attached storage (NAS), read-only memory, random-accessmemory, CD-ROMs, CD-Rs, CD-RWs, magnetic tapes, and other optical andnon-optical data storage devices. The computer readable medium can alsobe distributed over a network coupled computer systems so that thecomputer readable code is stored and executed in a distributed fashion.

It will be further appreciated that the instructions represented by theoperations in the above figures are not required to be performed in theorder illustrated, and that all the processing represented by theoperations may not be necessary to practice the invention. Further, theprocesses described in any of the above figures can also be implementedin software stored in any one of or combinations of the RAM, the ROM, orthe hard disk drive.

Although the foregoing invention has been described in some detail forpurposes of clarity of understanding, it will be apparent that certainchanges and modifications may be practiced within the scope of theappended claims. Accordingly, the present embodiments are to beconsidered as illustrative and not restrictive, and the invention is notto be limited to the details given herein, but may be modified withinthe scope and equivalents of the appended claims.

1. A method of forming a feature comprising: receiving a semiconductorsubstrate having a first layer; forming a mask of a first material onthe first layer, wherein forming the mask includes forming a mask layeron the first layer and forming at least one opening in the mask layer,the at least one opening in the mask layer having an incorrect profileof at least one side of the opening or a bottom of the opening;correcting the profile of the at least one side of the opening or abottom of the opening in the mask layer including at least one of:removing a bottom portion of at least one side of the at least oneopening in the mask layer such that the at least one side issubstantially perpendicular to top surface of the mask layer; or addinga second portion material to at least one side of the opening in themask layer such that the at least one side of the opening is substantialperpendicular to a top surface of the mask layer; and forming a featurein the first layer.
 2. The method of claim 1, further comprisingremoving the mask layer from the first layer.
 3. The method of claim 1,wherein forming the at least one opening in the mask layer includesforming the at least one opening in the mask layer with aphotolithographic process wherein the photolithographic process isoptimized for a first critical dimension and wherein the at least oneopening in the mask layer has a second critical dimension that issubstantially less than the first critical dimension.
 4. The method ofclaim 1, wherein forming the at least one opening in the mask layerincludes forming the at least one opening in the mask layer with aphotolithographic process wherein the photolithographic process isoptimized for a first density of openings and wherein the mask layer hasa second density of openings that is substantially greater than thefirst density of openings.
 5. The method of claim 1, wherein removingthe bottom portion of the at least one side of the opening in the masklayer includes at least one of a low pressure etch process or aselective deposition process.
 6. The method of claim 5, wherein the lowpressure etch process includes an etch process pressure of less thanabout 70 milliTorr.
 7. The method of claim 5, wherein the selectivedeposition process includes an deposition process system pressure ofgreater than about 50 milliTorr.
 8. The method of claim 1, whereinadding a second portion of material to the at least one side of theopening in the mask layer includes at least one of a low pressure etchprocess or a selective deposition process.
 9. The method of claim 1,further comprising narrowing the corrected profile of the opening in themask layer.
 10. The method of claim 9, wherein narrowing the correctedprofile of the opening in the mask layer includes adding a third portionof material to the at least one side of the opening in the mask layer.11. The method of claim 9, wherein the feature formed in the first layeris substantially equal to or less than the narrowed opening in the masklayer.
 12. The method of claim 1, wherein correcting the profile of theat least one opening in the mask layer includes removing a bottomportion of at least one side of the at least one opening in the masklayer such that the bottom of the opening is substantially parallel tothe top surface of the mask layer and that the bottom of opening has adesired width.
 13. A method of forming a feature comprising: receiving asubstrate having a first layer; forming a mask of a first material onthe first layer, wherein forming the mask includes forming a mask layeron the first layer and forming at least one opening in the mask layer,the at least one opening in the mask layer having an incorrect profileof at least one side of the opening or a bottom of the opening, whereinthe at least one opening in the mask layer is formed with aphotolithographic process, the photolithographic process is optimizedfor a first critical dimension and wherein the at least one opening inthe mask layer has a second critical dimension that is substantiallyless than the first critical dimension; correcting the profile of the atleast one side of the opening or a bottom of the opening in the masklayer including: removing a first portion of at least one side of theopening in the mask layer such that the at least one side issubstantially perpendicular to top surface of the mask layer; and addinga second portion of material to at least one side of the opening in themask layer such that the at least one side is substantiallyperpendicular to top surface of the mask layer; and forming a feature inthe first layer.
 14. The method of claim 13, wherein the first portionis removed from the at least one side of the opening in the mask layersubstantially simultaneously when the second portion of the material isadded to the at least one side of the opening in the mask layer.